Protecting individuals from sunlight is important due to the deleterious cosmetic and medical effects of sunlight on the skin and subcutaneous tissues, both immediately after exposure and after prolonged and/or repeated exposure. Immediately, sunlight can cause reddening with an accompanying painful sunburn. Over time, repeated exposure to sunlight can cause premature aging of the skin and a loss of elastic quality.
Medically, sunlight is a contributing factor to the development of diseases such as melanoma and squamous and basal cell carcinomas. Probably the most common type of longer term damage is basal cell carcinoma which, although seldom fatal, can be disfiguring and requires medical attention. Another somewhat less common disease resulting from sun exposure is squamous cell carcinoma. Although also generally non fatal, squamous cell carcinoma can spread through the body if left untreated. The most deadly and feared cancer associated with sun exposure is malignant melanoma which spreads to other parts of the body unless detected and treated at an early stage of the disease.
Xeroderma pigmentosum is a rare pigmentary and atrophic autosomal recessive disease which causes extreme cutaneous photosensitivity to ultraviolet light and affects all races. This disease requires highly undesirable precautions to prevent exposure to light to the extent of remaining indoors in darkened rooms.
The components of sunlight that have been identified as causing deleterious medical effects are wavelengths in the ultraviolet spectrum, UVA (320-400 nm), UVB (280-320 nm) and UVC (200-280 nm). Both the UVA and UVB ranges have been found to contribute to skin damage. The UVC component of sunlight also causes deleterious medical effects but is largely removed by the ozone layer. However, UVC is likely to become a greater threat as the ozone layer is depleted.
Fabrics have been designed which reduce the transmission of the UVA and UVB radiation, e.g. U.S. Pat. Nos. 5,414,913 and 5,503,917. Some fabrics made with a tightly woven fabric will reduce the transmission of UV radiation.
Dyes have also been developed for increasing the SPF rating of fabric. Examples of patents and patent applications describing such dyes include U.S. Pat. No. 5,637,348; published PCT applications WO 9625549, WO 9417135, and WO 9404515; published British applications GB 2298422 and GB 2289290; published German applications DE 19613671, DE 19613251, DE 19606840, and DE 19600692; and published European applications EP 708197, EP 707002, EP 693483, EP 682145, EP 683264, and EP 659877.
U.S. Pat. No. 5,134,025 discloses the use of particles for the sole use of reflecting UV rays, in particular as an aid to creating a suntan rather than minimizing UV exposure as in the sun protective clothing application.
A need exists for ways to protect people from UVA, UVB and UVC light rays. UV protection should be easy and unobtrusive for an individual to use. UV protection should also be inexpensive to implement.